Antifriction alloy and method of manufacture



UNITED STATES PATENT OFFICE.

LAYTON M. PARKHURST, OF CHICAGO, ILLINOIS, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO H. KRAMER & (30., OF CHICAGO, ILLINOIS, A CORPORATION OF ILLI- NOIS.

ments in Antifriction Alloys and Methods I sure,

of Manufacture; and I do hereby declare that the following is a full, clear, and exact description of the same.

This invention relates to anti-friction alloys and method of manufacture.

Anti-friction alloys should possess three properties; low coefiicient of friction, sufficient hardness to withstand bearingpresand resistance to heat not only as regards fusibility but also oxidation, crystallization, and segregation of constituents under heat.

Lead possesses a very low coefficient of friction but is not hard enough to stand even moderate bearing pressures. "Even Babbitt metal cannot be used with bearing pressures over 100 lbs. per square inch. Further, lead and antimony have the property of combining with each other in all pro portions withoutimpairing the anti-friction plil'operties of either. The antimony hardens t e of 80 parts o'f lead by weight with 20 parts of antimony possesses greater antifriction or wearing properties, or will stand a higher speed without heat or' abrasion than any other proportions of these two metals. Such an alloy is not, however, sufiiciently' hard for automobile truck hearings or the like which have high bearing pressures around 600 to 700 lbs. persquare inch. Further, such an alloy is not resistant to heat and its use, therefore,is usually restricted to light.

. high-speed machinery.

None of these antifrictionalloys, including those sold under the name of Babbitt metal, has a Dr. Brinnells scale. I

One of the objects of the present'invention is to provide an antifriction alloy capable of being used successfully with shaft pressures up to and even exceeding 1,000 lbs. per square inch.

Afurther obi ect is to provide an antifriction alloy which is resistant to the action of heat.

It is also an object of the invention to pro vide a method of making an antifriction cat which copper melts.

lead, and when mixed in the proportion hardness of over 22 or 23 on ANTIFBICTION ALLOY AND METHOD OF MANUFACTURE. I

Specification of Letters Patent. Patented NO 16, 19,20,

1920. Serial ml 364,035.

excess of about 350'C. I

In general it is an object of this invention to provide an. improved antifriction alloy and method of manufacturing the same.

I have found that the hardness of a leadantimony alloy may be increased by replacing a part of the antimony by tin and copper. I have also discovered that greatly im. proved results are obtained by alloying the tin and copper at a temperature below that A further discovery I have made is that small additions of certain substances, notably phosphorus, increases the hardness very mater ally.

An antifriction alloy adapted for use with bearing 'pressures up to 1,000 lbs. per square inch may be made as follows:

Lead 79% Antimony 12% Tin 6% Copper 2. 5 Phosphorus 0.5

and

other properties beyond useful limits. Or- V dinarily, owever, the proportions should be retained within the following limits: Lead 73%-85% Antimony 8 -14 Tin 5 7 'Gopp'efl 1.5 3.5 Phosphorus 0.25 0.7

It has been found in particular that usually additions of phosphorus above 0.7% tend'to soften instead of harden the product.

The melting points of the various constituent metals are as follows: lead 327-C.; antimony, 630C.; tin, 232C.; and copper, 10839-C. By adding the constituents in proper sequence the temperature of the melt may be retained below 350C. at all times; In the first place the tin-is melted and the copper added thereto, maintaining the temperature preferably not in'excess of 300. When the copper has completely dissolved in the tin and a true homogeneous alloy produced the necessary amount of antimony and phosphorus is added. This may,

if desired, be cast into blocks for incorporation with batches of lead at a later date. '10

The lead is melted and the requisite amount of the above alloy added thereto to give a metal having the desired composition. In

some casesthe antimony may be added toy the lead instead of to the tin-copper alloy all proportions.

since antimony readily alloys with lead in On e. of'the great advantages of keeping the temperature of the tin-copper alloy below 300C. is avoidance of oxidation. Such alloys not only readily oxidize but also dis- 'solveoxy en which is givenvofl' again on Ecooling. uch oxidation and '(or) solution 10f oxygen as may take place'at 300 C. is

counteracted by the phosphorus added which i combines with the oxygen yielding a homo-. geneous, dense, and strong product. phosphorus, therefore, has two .functions: first, to-increase' thehardness', and second,

1 ,to de-oxidize the alloy.

" While I have described my invention in a preferred'form', I am aware that changes and modifications may be made in the inand finally mixing the product with lead.

' subscribing witnesses, p M. PABKHURST.

gredients employed and the proportions and manner in which they are mixed without departing from the principles of'my invention, and I do not, therefore, purpose limiting the'patent granted otherwise than ne- 4. The method of making an antifriction alloy comprising melting tin and alloyinga smaller proportion of copper therewith at a temperature not ,substantiall in excess of 300C., adding thereto antimony and phosp horus andfinally-mixing the product with molten lead. The In testimony whereof I have hereunto presence of two subscribed my name in the LAYTON Witnesses: RmsDAL'n ELLIS,

EARL M. HARDINE. 

